1. Technical Field of the Invention
The disclosure relates to an electronic device and a start-up method thereof which can be applied to the electronic device start-up technology and more particularly applied to the power over Ethernet (POE) technology.
2. Description of the Related Art
Power over Ethernet is a relatively novel power supply technology recently, which can transmit power and data to a corresponding electronic device via a twisted pair in the Ethernet. Since the power over Ethernet technology can enable the electronic device to be powered without modifying the cable architecture of the Ethernet, electronic devices (such as an Internet Phone, wireless access point, a Webcam, a hub, and a computer) applying the POE technology can be used without additional power supply sockets, which lowers the construction costs of the whole equipment system.
The POE technology is mainly divided into two parts: power supply apparatus as the powering end and a powered device (PD) as the powered end. In addition, the existing power over Ethernet technology supports two basic specifications: one is the 802.3af specification (also referred to as 802.3at first type specification) which provides a smaller electronic power (such as 12.95 watt (w)). Another is the 802.3at specification, and the 802.3at first type specification is compatible with the 802.3af specification, while the 802.3at second type specification can provide a larger electronic power (such as 25.5 watt (w) so as to drive a powered device with higher power consumption requirements.
The power supply apparatus can also be classified as a physical layer (Layer1) or a link layer (Layer2) when realizing how to detect the POE specification (such as 802.3af (802.3at first type) or 802.3at second type) of the powered device. Applying the physical layer (Layer1) is that, for example, the corresponding hardware is provided at both the power supply apparatus and the powered device, thereby actively detecting the POE specification of each other through the matched hardware. Although applying this method is very convenient, higher hardware costs are required. In addition, applying the above-mentioned link layer (Layer2) is that, for example, when the powered device requires a larger amount of electronic power, the powered device actively communicates with the power supply apparatus via a network using the link layer discovery protocol during operation, so as to change the POE specifications thereof from 802.3af (802.3at first type) to 802.3at second type.
However, if applying the link layer (Layer2), an ordinary powered device cannot start up the network function to change the POE specification before booting. Therefore, for electronic products requiring higher power consumption during booting, these electronic products cannot utilize the power over Ethernet technology to be powered during booting.